In uranium solution mining processes stripping solutions are injected underground where they solubilize uranium. The recovery solutions are pumped to the surface and are processed to remove the uranium. These recovery solutions, however, are frequently supersaturated with dissolved calcite (calcium carbonate). The calcium carbonate must be precipitated before the solution can be processed, otherwise the calcium carbonate precipitates throughout the processing equipment, rendering it inoperable.
When the calcium carbonate precipitates some of the uranium in solution precipitates with it, causing a loss of uranium and creating a radioactive waste disposal problem. Moreover, radium, a daughter product of uranium, is also dissolved in the stripping solution and is also precipitated with the uranium, further increasing the radioactivity of the precipitate.
While some processes are being used to recover the uranium from the calcium carbonate precipitate, they still leave large quantities of solid waste contaminated with radioactive radium. Disposal of radioactive waste is very expensive. The waste must be placed in steel drums, transported to a disposal site, and stored in a guarded area. Reduction in the quantity of solid wastes is therefore very desirable as it reduces the danger of environmental contamination and the cost of storage.